Modelling the warm-up phase of the starting processes of high-intensity discharge lamps

Based on the extensive experimental investigation on the starting process inside metal-halide lamps, this study presents a unified high intensity discharge (HID) lamp model, which can predict the electrical characteristics of a HID lamp in both warm-up and steady-state operations. The authors propose and verify that the warm-up phase can be described by its initial operating state, final operating state and the heating time constant of the lamp. The model can be implemented into a circuit model based on commercial simulation packages such as PSpice. Such a model can be used by ballast circuit designers and engineers to evaluate the influence of the transient warm-up process on the lighting network system. This is believed to be the first HID lamp model including both the warm-up and steady-state operations.